Synchronizing Record Definitions With Tables

怼烎@ 2021-12-15 02:49 186阅读 0赞

Evaluating Modifications to Field and Record DefinitionsIf you change either a field definition or a record definition, you might have to alter the associated SQL table to synchronize it, depending on what the changes are. Use the following table to determine if changes to the table are required.

<table style="border-right:medium none;border-top:medium none;margin-left:-71.1pt;border-left:medium none;border-bottom:medium none;border-collapse:collapse;"> 
 <tbody> 
 <tr> 
 <td style="border-right:1pt solid;border-top:1pt solid;background:#e0e0e0;border-left:1pt solid;width:85.5pt;border-bottom:1pt solid;"> Category </td> 
 <td style="border-right:1pt solid;border-top:1pt solid;background:#e0e0e0;border-left:medium none;width:129pt;border-bottom:1pt solid;"> Table Structure Changes (Requires Create or Alter Table) </td> 
 <td style="border-right:1pt solid;border-top:1pt solid;background:#dfdfdf;border-left:medium none;width:129pt;border-bottom:1pt solid;"> Index Changes (Requires Create Index) </td> 
 <td style="border-right:1pt solid;border-top:1pt solid;background:#dfdfdf;border-left:medium none;width:129.05pt;border-bottom:1pt solid;"> Online System Changes (No database changes required) </td> 
 </tr> 
 <tr> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:1pt solid;width:85.5pt;border-bottom:1pt solid;"> Field properties </td> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:medium none;width:129pt;border-bottom:1pt solid;"> Field name Length Type Delete/Add field from record definition </td> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:medium none;width:129pt;border-bottom:1pt solid;"> N/A </td> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:medium none;width:129.05pt;border-bottom:1pt solid;"> Format Long name Short name Translate table values </td> 
 </tr> 
 <tr> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:1pt solid;width:85.5pt;border-bottom:1pt solid;"> Record field use properties </td> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:medium none;width:129pt;border-bottom:1pt solid;"> N/A </td> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:medium none;width:129pt;border-bottom:1pt solid;"> Key (new) Alternate search key Key direction (ascending or descending) Duplicate order key </td> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:medium none;width:129.05pt;border-bottom:1pt solid;"> Search key (if already a key) List box item Defaults (value and page control) Auto update Field audits </td> 
 </tr> 
 <tr> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:1pt solid;width:85.5pt;border-bottom:1pt solid;"> Record field edits properties </td> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:medium none;width:129pt;border-bottom:1pt solid;"> Value required (Long Character, Date, Time, DateTime, Image) </td> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:medium none;width:129pt;border-bottom:1pt solid;"> N/A </td> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:medium none;width:129.05pt;border-bottom:1pt solid;"> Prompt table edit Translate table edit Yes/No edit Value required (Numeric, Character) Reasonable date check </td> 
 </tr> 
 <tr> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:1pt solid;width:85.5pt;border-bottom:1pt solid;"> Record field PeopleCode </td> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:medium none;width:129pt;border-bottom:1pt solid;"> N/A </td> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:medium none;width:129pt;border-bottom:1pt solid;"> N/A </td> 
 <td style="border-right:1pt solid;border-top:medium none;border-left:medium none;width:129.05pt;border-bottom:1pt solid;"> PeopleCode </td> 
 </tr> 
 </tbody> 
</table>

If you change the table structure, you must either build or alter the table. The Alter Table process is similar to the Create Table process, except that it does not drop existing application data tables and the data that they contain.

<table style="margin-left:-102.6pt;border-collapse:collapse;"> 
 <tbody> 
 <tr> 
 <td style="width:108.9pt;"> Drop column if data present </td> 
 <td style="width:288pt;"> Select to drop the column and data and write a warning to the build log.&nbsp;You are prompted at runtime to confirm this option if there is potential data loss. </td> 
 </tr> 
 <tr> 
 <td style="width:108.9pt;"> Skip record if data present </td> 
 <td style="width:288pt;"> Select to skip the record with data and write an error message to the log.&nbsp;Processing continues with the next record. </td> 
 </tr> 
 <tr> 
 <td style="width:108.9pt;"> Truncate data if field too short </td> 
 <td style="width:288pt;"> Select to alter the record and write a warning message to the build log.&nbsp;You are prompted at runtime to confirm this option if there is potential data loss. </td> 
 </tr> 
 <tr> 
 <td style="width:108.9pt;"> Skip record if field too short </td> 
 <td style="width:288pt;"> Select to skip the record with excess data and write an error message to the build log.&nbsp;Processing continues with the next record. </td> 
 </tr> 
 <tr> 
 <td style="width:108.9pt;"> Adds, Changes, Renames, and Deletes </td> 
 <td style="width:288pt;"> Select all check boxes so that record definition changes are passed to the altered table.&nbsp;Clear a box if you don’t want a change in the altered table (a deleted column, for example). </td> 
 </tr> 
 <tr> 
 <td style="width:108.9pt;"> Alter even if no changes </td> 
 <td style="width:288pt;"> When fields are rearranged within a record definition and no other properties are changed, some database platforms do not pick up the new field order as a change.&nbsp;To synchronize the new order in the table, select this option. </td> 
 </tr> 
 </tbody> 
</table>

##### Alter Table Options #####

There are two options for altering tables: Alter in Place and Alter by Table Rename.  Normally you accept the default value assigned.

<table style="border-collapse:collapse;"> 
 <tbody> 
 <tr> 
 <td style="width:108.9pt;"> Alter in Place </td> 
 <td style="width:297.9pt;"> Performs the SQL Alter command to change the structure of an application table.&nbsp;New columns (if any) are placed at the end of the table. </td> 
 </tr> 
 <tr> 
 <td style="width:108.9pt;"> Alter by Table Rename </td> 
 <td style="width:297.9pt;"> Creates a temporary table based on the record definition, copies data from the original table, drops the original table, and renames the temporary table with the original name. </td> 
 </tr> 
 </tbody> 
</table>

If new fields are being added to the record definition, and field order is important, you select the Alter by Table Rename method.

转载于:https://www.cnblogs.com/GoDevil/archive/2008/12/26/1362830.html